CVE-2026-74572

Estado: RecibidaAlta (7.5)—

In the Linux kernel, the following vulnerability has been resolved:

btrfs: zoned: fix deadlock between metadata writeback and transaction commit

When writing out metadata extent buffers in a zoned filesystem, btree_writepages() holds fs_info->zoned_meta_io_lock across the whole writeback loop, including the call to btrfs_check_meta_write_pointer() -> check_bg_is_active().

For the tree-log block group, check_bg_is_active() may fail to activate the zone and fall back to btrfs_zone_finish_one_bg() to free an active zone. That path waits for the running transaction to commit while still holding zoned_meta_io_lock, but the committer needs that same lock to write out the tree extents, so the two tasks deadlock:

Leer descripción completaMostrar menos

The sibling branch in check_bg_is_active() already drops zoned_meta_io_lock around do_zone_finish() for this exact reason. Do the same in the tree-log branch: release the lock around btrfs_zone_finish_one_bg() and re-acquire it afterwards. The lock only protects fs_info->active_{meta,system}_bg, which this branch does not touch, and ctx->zoned_bg keeps a reference to the block group across the unlock, so nothing is lost while the lock is dropped.

This hang occasionally reproduces with fstests generic/475 on a zoned btrfs filesystem.

Detalles técnicos trazas, registros y código del informe original

  Task A (kworker, metadata writeback)      Task B (fsstress, transaction commit)
  ------------------------------------      -------------------------------------
  wb_workfn()                               btrfs_commit_transaction(T)
   btree_writepages()                        btrfs_write_and_wait_transaction()
    btrfs_zoned_meta_io_lock()                btrfs_write_marked_extents()
    btrfs_check_meta_write_pointer()           btree_writepages()
     check_bg_is_active() [treelog_bg]          btrfs_zoned_meta_io_lock()
      btrfs_zone_finish_one_bg()               <blocks on zoned_meta_io_lock,
       btrfs_zone_finish()                      held by Task A>
        do_zone_finish()
         btrfs_inc_block_group_ro()
          btrfs_wait_for_commit()
           <blocks waiting for commit
            of transaction T, done by
            Task B>

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.63%
Percentil entre todas las CVEs puntuadas: 48
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

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Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-74572",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "13bb483d32abb6f8ebd40141d87eb68f11cc2dd2",
              "lessThan": "18577e77c2c8adaadf1f7c6e9bcd1c0b14e5dcdd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "13bb483d32abb6f8ebd40141d87eb68f11cc2dd2",
              "lessThan": "c3320873e0c04ce7b746fc8fe948f07bbbbdec33",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "13bb483d32abb6f8ebd40141d87eb68f11cc2dd2",
              "lessThan": "deddd28fd83c264ee2ff5cd6b34449a9f1be6112",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "13bb483d32abb6f8ebd40141d87eb68f11cc2dd2",
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              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "13bb483d32abb6f8ebd40141d87eb68f11cc2dd2",
              "lessThan": "1ebe51c29fa9755d5b2fea28727c051117907cf8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "fca3a1cd3ba47f1815e0c0fcdc9aafaf02ee0a75",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6.5.5",
              "lessThan": "6.6",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/btrfs/zoned.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.6",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/btrfs/zoned.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T13:18:02.837",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/18577e77c2c8adaadf1f7c6e9bcd1c0b14e5dcdd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1ebe51c29fa9755d5b2fea28727c051117907cf8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/75859a7cd77cd2ddaddbcb963e3fcd34738953af",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c3320873e0c04ce7b746fc8fe948f07bbbbdec33",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/deddd28fd83c264ee2ff5cd6b34449a9f1be6112",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zoned: fix deadlock between metadata writeback and transaction commit\n\nWhen writing out metadata extent buffers in a zoned filesystem,\nbtree_writepages() holds fs_info->zoned_meta_io_lock across the whole\nwriteback loop, including the call to btrfs_check_meta_write_pointer() ->\ncheck_bg_is_active().\n\nFor the tree-log block group, check_bg_is_active() may fail to activate\nthe zone and fall back to btrfs_zone_finish_one_bg() to free an active\nzone. That path waits for the running transaction to commit while still\nholding zoned_meta_io_lock, but the committer needs that same lock to\nwrite out the tree extents, so the two tasks deadlock:\n\n  Task A (kworker, metadata writeback)      Task B (fsstress, transaction commit)\n  ------------------------------------      -------------------------------------\n  wb_workfn()                               btrfs_commit_transaction(T)\n   btree_writepages()                        btrfs_write_and_wait_transaction()\n    btrfs_zoned_meta_io_lock()                btrfs_write_marked_extents()\n    btrfs_check_meta_write_pointer()           btree_writepages()\n     check_bg_is_active() [treelog_bg]          btrfs_zoned_meta_io_lock()\n      btrfs_zone_finish_one_bg()               <blocks on zoned_meta_io_lock,\n       btrfs_zone_finish()                      held by Task A>\n        do_zone_finish()\n         btrfs_inc_block_group_ro()\n          btrfs_wait_for_commit()\n           <blocks waiting for commit\n            of transaction T, done by\n            Task B>\n\nThe sibling branch in check_bg_is_active() already drops zoned_meta_io_lock\naround do_zone_finish() for this exact reason. Do the same in the tree-log\nbranch: release the lock around btrfs_zone_finish_one_bg() and re-acquire\nit afterwards. The lock only protects fs_info->active_{meta,system}_bg,\nwhich this branch does not touch, and ctx->zoned_bg keeps a reference to\nthe block group across the unlock, so nothing is lost while the lock\nis dropped.\n\nThis hang occasionally reproduces with fstests generic/475 on a zoned\nbtrfs filesystem."
    }
  ],
  "lastModified": "2026-08-17T06:19:55.507",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}